Microbiologists often hope to answer key questions – which microbes are present, and what are they doing? – in non-destructive ways. After all, if you’re changing the very system you’re hoping to analyze, how can you be sure that your measurements reflect native conditions?

The importance of non-destructive analyses takes on a new dimension when objects of cultural significance are involved. Disruptive techniques won’t merely perturb the natural system, but could destroy a priceless artifact. Leonardo da Vinci’s famous self-portrait, drawn around 1510 using red chalk, is one such work. From the fine, shadowed lines, a wizened man in three-quarter view emerges from the page, casting a solemn stare into the distance.

But time has taken a toll: the paper drawing has been infested with “foxing spots” over the centuries, an affliction of reddish-brown spots that has bedeviled collectors and conservationists for years. But what is causing the marks, and could they be removed to preserve this and other works?

Previous researchers have wrestled with this conundrum for decades. A time-series of photographs suggests that the spots were around by 1952, and have not visibly increased in number or intensity since. Some scientists proposed a biological influence, while others favored a chemical one. Subsequent teams in recent years have tried to pinpoint a biological origin of the blemishes, using cotton swabs and a range of media to cultivate the culprit. With little success, researchers were at a loss.

Improved sampling and sequencing tools now offer an additional dimension of investigation. Guadalupe Pinar, a senior scientist at the University of Natural Resources and Life Sciences in Vienna, led a team of researchers thatrecently published molecular and microscopic evidence pointing to prominent fungal involvement. The scientists extracted DNA from the drawing, amplified fungus-specific sequence, and cloned recovered fragments to identify the responsible organisms. These efforts showed a fungal community dominated by several species of the Ascomycota phylum, and, in particular, a previously uncharacterized Acremonium species. Their electron microscopy efforts revealed a zoo of fungal forms: smooth spheres wrapped in filaments, spiky cells congregating on a mysterious particle, and flattened disks with cross-hatched scars.

So while biological involvement is clear, Pinar suggests that the foxing spots result from a two-stage, chemically-induced process. First, dust-borne iron particles land randomly on the paper, disrupting the cellulosic structure and generating a nucleation point of damage. With an opening, fungal organisms take hold, burrowing into the paper and waiting out the extended dry, low-nutrient periods by shutting down metabolism. When energy is available, the microbes spit out oxalic acid, which precipitates as calcium oxalate crystals and causes further disruption.

For conservationists, the message is mixed. On the one hand, it’s a convincing validation of the idea that future technologies will be better suited to answer difficult questions. If earlier researchers had had their way in 1987, da Vinci’s drawing would have been soaked in ethylene oxide, an intervention that could have caused irreparable damage. On the other hand, modern techniques like microsampling, single-cell genetic analyses, and electron microscopy may be sufficient to address many similar conundrums.

Treatment strategies, however, are still far from perfect, but understanding the precise composition of the spots is an important pre-requisite for developing a conservation game plan. Once that is established, work will begin in a race against biology to keep da Vinci from fading further into the centuries-old paper.

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Afghanistan arrested and handed over several Muslim Uighur militants from China’s west in an effort to persuade China to use its influence with Pakistan to help start negotiations with the Taliban, Afghan security officials said on Friday.

22 Şubat 2016, 20:43

Afghanistan arrested and handed over several Muslim Uighur militants from China’s west in an effort to persuade China to use its influence with Pakistan to help start negotiations with the Taliban, Afghan security officials said on Friday.

The deal sheds light on China’s increasing importance in Afghanistan and Pakistan, with its involvement in efforts to end the war with Taliban, who have been fighting since 2001 to re-establish Islamist rule in Afghanistan.

Hopes for a peace process were raised on Thursday when Pakistani and Afghan officials said members of the Taliban leadership had signaled they were willing to begin talks as soon as next month.

The apparent Taliban change of position was said to have been made under pressure from Pakistan, although the official Taliban spokesman denied any move toward negotiations with the Afghan government.

Pakistan has been under pressure from China, which is concerned about Islamists among its Muslim minority, to step up pressure against militants.Three senior Afghan police and intelligence officials described the operation last month to capture ethnic Uighur militants, members of a separatist movement opposed to Beijing’s rule over the Xinjiang region, which is home to the Turkic-speaking, mostly Muslim Uighurs.

“We offered our hand in cooperation with China and in return we asked them to pressure Pakistan to stop supporting the Taliban or at least bring them to the negotiating table,” said one of the security officials, who attended a meeting with Chinese officials to arrange transfer of the prisoners.

Chinese officials in Beijing and at the embassy in Kabul did not respond to requests for comment.

The Uighurs, who the Afghan officials said had trained in militant camps across the border in Pakistan, were handed over to Chinese officials last month.

A second security official said a total of 15 Uighurs were arrested – three in the capital, Kabul, and 12 later in the eastern province of Kunar bordering Pakistan.

They had been in contact with al Qaeda and other militants operating in Pakistan, according to a member of Afghanistan’s intelligence agency.

A Pakistani Taliban commander in the border area said by telephone that a group of Uighurs had been based in the Pakistani border region of North Waziristan but left when the Pakistani army launched an offensive there last year.

“They have shifted to Afghanistan,” he said.

‘PLAYING ITS ROLE’

China has increasingly been concerned about activists from Xinjiang getting militant training in Pakistan. It says Uighur militants were behind attacks in Xinjiang and other parts of the country in recent years in which hundreds have been killed.

Exiled Uighur groups and human rights activists, however, say repressive government policies in Xinjiang, including controls on Islam and on Uighur culture, have provoked unrest.

China’s concerns have led it to engage in the so far fruitless effort to negotiate an end to the Afghan war, said Barnett Rubin, a former State Department official who is now a senior fellow at the Center on International Cooperation.

In particular, China is believed to have used its influence with Pakistan to persuade it that it was not in Pakistan’s interests to turn a blind eye to the Afghan Taliban and other militants operating along its border.

“Pakistan’s attitude to militant groups fighting in Afghanistan has evolved … China has played a role in Pakistan’s evolution because China is very concerned about militants from Xinjiang province receiving training in Pakistan,” Rubin said.

China is likely to have played a significant role in moves toward starting talks with the Taliban, he said.

“I’m sure they have weighed in quite decisively, quietly.”

Pakistan is seen as having other reasons for pushing the Afghan Taliban to talk to Kabul, in particular the hope of Afghan help in tackling Pakistani Taliban hiding in east Afghanistan and launching attacks in Pakistan, including the massacre of 153 people at an army-run school in December.

Pakistan has long seen the Afghan Taliban as a tool if old rival India were to become too influential in a hostile Afghanistan.

But Afghan President Ashraf Ghani, who took office last year, has made improving relations with both Pakistan and China a cornerstone of his administration.

Ghani’s first foreign visit was to Beijing in October when he assured Chinese President Xi Jinping of Afghanistan’s help in fighting militants.

Last week in Pakistan, visiting Chinese Foreign Minister Wang Yi said China would help mediate in efforts to engage the Afghan Taliban in negotiations.

A week later, Pakistan’s powerful army chief visited Afghanistan with a message for Ghani that Taliban leaders had signaled they were open to talks.

It is not clear how significant Afghanistan’s arrest of the Uighurs was in the push for negotiations. A Pakistani military officer said China was “playing its role” in the effort.

Pakistani Foreign Office spokeswoman Tasnim Aslam said it was unfair to suggest that China or any other outsider was behind Pakistan’s involvement in pushing for talks.

“Peace and stability in Afghanistan are in Pakistan’s interest,” she said.

(Additional reporting by Katharine Houreld and Mehreen Zahra-Malik in Islamabad and Saud Mehsud in Dera Ismail Khan, Pakistan; Writing by Kay Johnson; Editing by Robert Birsel)

The World Uyghur Congress (WUC) is pleased to announce that it’s 5th General Assembly will be taking place in Berlin from 27-29 April. The WUC will be expecting around 100 Uyghur delegates to attend both events, as well as a number of academics, experts, activists, members of civil society and political figures to be invited to the Opening Ceremony, which will also be open to the public.

The meeting will prove to be the most important since the founding of the organization back in 2004 with the merger of the East Turkestan National Congress and the World Uyghur Youth Congress. A Preparation Committee, including members from both from the international headquarters in Munich and from affiliate organizations around the world, will be formed to prepare for the meeting. The Committee will develop draft amendments to the WUC Charter which will then be submitted to the General Assembly for approval. The Committee will also determine the number and eligibility of the delegates that will be able to attend the Assembly.

During the 5th General Assembly, new WUC leadership will be elected by the delegates and the WUC’s activity and its financial reports will be discussed. The General Assembly will also finalise and approve of a new Charter for the organization and will involve a shift within leadership ranks to ensure that younger members of the Uyghur diaspora community are involved in advocacy activities. The meeting will also look to develop a strategy to attract more engagement from Uyghur intellectuals abroad, and to develop the working strategy of the organization in the upcoming years in order to more effectively raise the Uyghur issue in international fora.